Genome comparison of Actinomyces naeslundii with 25 known probiotics

Introduction: Actinomyces naeslundii is an oral microbiome that has been suggested to involve in actinomycosis particularly in immunocompromised patients. However, studies have also shown that the bacterium can inhibit the colonisation of Candida albicans and cariogenic bacterium, Streptococcus mutans. Even though various studies have been conducted to characterise A. naeslundii, however, the role of the bacterium in the oral cavity either to induce pathogenicity or to improve oral health remain unclear. The objective of this study is to determine the role of A. naeslundii in the oral cavity using bioinformatic tools with the hypothesis that A. naeslundii possesses genome similarity to oral probiotics. Materials and method: The study was conducted by data mining of the genomic sequences of A. naeslundii NCTC10301 from GenBank. Following that, genomic comparison was performed with 25 species of well-known probiotics. MAUVE version 2.3.1 was used to find similarities between A. naeslundii with the known probiotics through identification of potential relevance probiotic properties in A. naeslundii. Phylogenetic tree was constructed using PHYLIP package to identify evolutionary relationship of A. naeslundii with the known probiotics. The 16s rRNA sequences of A. naeslundii and known probiotics were harvested from GenBank using BLAST. Finally, the functions of all A. naeslundii genes that shared similarity with known probiotics were identified using INTERPRO. Result: Genome comparison analysis of the present study showed that A. naeslundii genome exhibited high similarity to Bifidobacterium species such as B. animalis subsp. lactis, B. bifidum, B. longum and B. breve. In addition, phylogenetic tree analysis showed that Bacillus species, B. subtilis and B. cereus , appeared to clade together with A. naeslundii , with bootstrap value of 98%. Conclusion: A. naeslundii had high similarity with probiotic Bifidobacterium species thus supported the hypothesis of the present study that A. naeslundii possesses genome similarity to oral probiotic

Probiotic inhibits oral carcinogenesis: A systematic review and meta-analysis

Objectives: This systematic review aimed to investigate the effects if probiotics can inhibit oral carcinogenesis. Design: PubMed, Web of Science, Scopus, and PLOS databases were searched up to February 2020 to identify randomised controlled trials that fulfilled the eligibility criteria. Joanna Briggs Institute (JBI) Critical Appraisal Tool was used for quality assessment of articles. This review was performed according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA-P) 2015 protocol guidelines. Result: The initial search retrieved 774 articles. Of these, only five articles were included in the qualitative synthesis. Two out of the five papers were further analysed for quantitative synthesis in meta-analysis. The majority of the included studies were found to be of “moderate quality”. The qualitative synthesis found four probiotics that exhibited potential therapeutic effects in oral carcinogenesis, includingAcetobacter syzygii, AJ2, Lactobacillus plantarum, and Lactobacillus salivarius REN. Among them, the application of L. salivarius REN re- sulted in a 95 % lower risk for developing oral cancer (p < 0.05). Conclusion: It is known that probiotics have the potential to inhibit oral carcinogenesis, thus supporting the hypothesis of the study. The ability of L. salivarius REN to inhibit the development of oral cancer suggested that this bacterium can be a potential inhibitory agent against oral carcinogenesis

Microbiome dysbiosis in depression: a systematic review

The objective of the study is to determine the role of microbiome dysbiosis in depression, with the hypothesis that dysbiosis involves in depression. PubMed, Science Direct and Scopus databases were used to identify the relevant studies which fulfilled the eligibility criteria. The searches were limited from January 2015 to July 2020. Joanna Briggs Institute (JBI) Critical Appraisal Tools was used for quality assessment of the studies. This review was performed according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA-P) 2015 proto- col guidelines. Initially, 1297 studies were identified. Of these, only three studies were included in the final synthesis. The studies were categorised as “high” quality. Dysbiosis of the gut microbiome, particularly by Faecalibacterium, Dialister, Acetivibrio, Collinsella, and Odofibacter, has been involved in depression. Treatment using probiotics such as Lactobacillus acidophilus, Bifidobacterium longum and Enterococcus faecalis was suggested to promote a balanced gut microbiome. Microbiome dysbiosis may involve in depression, thus supporting the hypothesis of the present study. However, no consensus was obtained to conclude which bacterial taxa are mostly relevant to depression